Recording disk drive capable of suppressing vibration of flexible printed circuit board

ABSTRACT

A fixing member is spaced from a head actuator by a predetermined distance. A flexible printed circuit board extends at least from the head actuator to the fixing member. The flexible printed circuit board is superposed on the surface of the fixing member. A viscoelastic layer and a protecting layer are over laid on the surface of the flexible printed circuit board. A clip clips all the fixing member, the flexible printed circuit board, the viscoelastic layer and the protecting layer together. When a head slider is positioned, the head actuator changes its attitude relative to a recording disk. The inertial force based on the rotation causes the first flexible printed circuit board to vibrate when the actuator block stops rotating. The viscoelastic layer serves to absorb this residual vibration of the first flexible printed circuit board. Vibration of the flexible printed circuit board can be suppressed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recording disk drive such as a harddisk drive (HDD). In particular, the invention relates to a recordingdisk drive comprising: a head actuator; a fixing member spaced from thehead actuator by a predetermined distance; and a flexible printedcircuit board attached to the head actuator so as to extend at leastfrom the head actuator to the fixing member.

2. Description of the Prior Art

A head actuator is incorporated in a hard disk drive (HDD) so as tochange its attitude relative to a magnetic recording disk. The headactuator comprises an actuator block coupled to a vertical supportshaft. Actuator arms are defined in the actuator block. A headsuspension is fixed to the corresponding actuator arm so as to support ahead slider at the tip end thereof. A first flexible printed circuitboard is attached to the actuator block so as to supply a sensingcurrent or a writing current to the head slider. The first flexibleprinted circuit board extends to the fixing member spaced from theactuator block by a predetermined distance.

Positioning holes are defined in the first flexible printed circuitboard. Pins are designed to protrude from the surface of the actuatorblock. When the first flexible printed circuit board is attached to theactuator block, the pins are inserted in the corresponding positioningholes. The first flexible printed circuit board is thus positioned onthe actuator block. The first flexible printed circuit board is thenfixed to the actuator block with a fastening member such as a screw. Asecond flexible printed circuit board is thereafter coupled to the firstflexible printed circuit board so as to extend from the actuator blockto the head slider. The second flexible printed circuit board isintegral to the head suspension. The head suspension and the secondflexible printed circuit board form a so-called long tale head.

When the head slider is positioned, the actuator block intermittentlyrepeats rotation around the vertical support shaft. The inertial forceof the rotation forces the first flexible printed circuit board tovibrate when the actuator block stop rotating. This residual vibrationis transmitted to the actuator block or the like. Reading and writingoperation of magnetic bit data is hindered.

If the second flexible printed circuit board is integral to the headsuspension, the displacement of the second flexible printed circuitboard is particularly limited when the second flexible printed circuitboard is to be positioned relative to the first flexible printed circuitboard. Accordingly, the first flexible printed circuit board must bepositioned on the actuator block at a higher accuracy prior to thepositioning of the second flexible printed circuit board. However, asufficient accuracy of the positioning of the first flexible printedcircuit board cannot be achieved with the conventional positioning hole.

SUMMARY OF THE INVENTION

It is accordingly an object of the present invention to provide arecording disk drive capable of suppressing vibration of a flexibleprinted circuit board when a head actuator changes its attitude. It isaccordingly another object of the present invention to provide arecording disk drive capable of positioning a flexible printed circuitboard o a head actuator with a higher accuracy. It is accordingly stillanother object of the present invention to provide a flexible printedcircuit board unit and a flexible printed circuit board greatly usefulto realize the aforementioned recording disk drive.

According to a first aspect of the present invention, there is provideda recording disk drive comprising: a recording disk; a head actuatordesigned to change its attitude relative to the recording disk; a fixingmember spaced from the head actuator by a predetermined distance; aflexible printed circuit board extending at least from the head actuatorto the fixing member and superposed on the surface of the fixing member;a viscoelastic layer overlaid on the surface of the flexible printedcircuit board; and a clip designed to clip all the fixing member, theflexible printed circuit board and the viscoelastic layer together.

The head actuator changes its attitude relative to the recording diskduring rotation of the recording disk in the recording disk drive. Theinertial force based on the rotation causes the flexible printed circuitboard to vibrate when the head actuator stops rotating. The viscoelasticlayer serves to absorb the vibration of the flexible printed circuitboard. The head actuator is prevented from receiving transmission of thevibration. Information can correctly be read and written.

Moreover, the viscoelastic layer serves to prevent the flexible printedcircuit board from contacting the clip. The viscoelastic layer serves toprotect the flexible printed circuit board. Protection of the flexibleprinted circuit board in this manner serves to avoid exposure of anelectrically-conductive pattern in the flexible printed circuit board.The electrically-conductive pattern can reliably be prevented from shortand disconnection. It should be noted that a protecting layer may beformed on the surface of the viscoelastic layer to receive the clip.

Furthermore, employment of the clip serves to realize an easierattachment of the flexible printed circuit board to the fixing member.Attachment process can be realized in more effective manner. On theother hand, a double-sided adhesive tape is interposed between theflexible printed circuit board and the fixing member in a conventionalrecording disk drive. When the double-sided adhesive tape is to beapplied, protection sheets must be peeled off from the both sides of thedouble-sided adhesive tape. This is inefficient.

A specific flexible printed circuit board unit may be provided torealize the aforementioned recording disk drive. The flexible printedcircuit board unit comprises a flexible printed circuit board attachedto a head actuator; and a viscoelastic layer overlaid on the surface ofthe flexible printed circuit board.

According to a second aspect of the present invention, there is provideda recording disk drive comprising: a head slider; a head actuatorcoupled to a support shaft for relative rotation so as to support thehead slider at the tip end of the head actuator; a pin protruding fromthe surface of the head actuator; a first flexible printed circuit boardattached on the head actuator, said first flexible printed circuit boarddefining a predetermined through bore designed to receive insertion ofthe pin; a second flexible printed circuit board received on the firstflexible printed circuit board on the head actuator. In this case, thefirst flexible printed circuit board includes: an insulating thin film;an electrically-conductive film piece located on the surface of theinsulating thin film; an insulating layer overlaid on the surface of theinsulating thin film and designed to partly cover over the contour ofthe electrically-conductive film piece; an aperture formed in theinsulating layer so as to expose the contour of theelectrically-conductive film along a first reference line on the surfaceof the insulating thin film. In addition, a clearance is established forthe insertion of the pin within the through bore in the direction of asecond reference line perpendicular to the first reference line.

When the first flexible printed circuit board is fixed on the headactuator, the first flexible printed circuit board is superposed on thesurface of the head actuator. The through bore of the first flexibleprinted circuit board receives the insertion of the pin. The contour ofthe electrically-conductive film piece within the aperture is thendetected with an image recognition apparatus. A shift is thus measuredalong the second reference line in the first flexible printed circuitboard. The amount of shift is measured based on a predeterminedreference position. The first flexible printed circuit board ispositioned on the head actuator based on the amount of shift measured.The positioning of the first flexible printed circuit board can berealized with a high accuracy. Since the predetermined clearance isestablished for the pin within the through bore in the direction of thesecond reference line, the first flexible printed circuit board can bedisplaced on the head actuator for establishment of a higher accuracy.

A specific flexible printed circuit board may be provided to realize theaforementioned recording disk drive. The flexible printed circuit boardcomprises: an insulating thin film; an electrically-conductive filmpiece located on the surface of the insulating thin film; an insulatinglayer overlaid on the surface of the insulating thin film and designedto partly cover over the contour of the electrically-conductive filmpiece; an aperture formed in the insulating layer so as to expose thecontour of the electrically-conductive film piece along a firstreference line on the surface of the insulating thin film; and anelongated opening formed at least through the insulating thin film, theelongated opening extending along a second reference line perpendicularto the first reference line.

According to a third aspect of the present invention, there is provideda recording disk drive comprising: a head slider; a head actuatorcoupled to a support shaft for relative rotation so as to support thehead slider at the tip end of the head actuator; a pin protruding fromthe surface of the head actuator; a first flexible printed circuit boardattached on the head actuator, said first flexible printed circuit boarddefining a predetermined through bore designed to receive insertion ofthe pin; and a second flexible printed circuit board received on thefirst flexible printed circuit on the head actuator. In this case, thefirst flexible printed circuit board includes: an insulating thin film;an electrically-conductive film piece located on the surface of theinsulating thin film and designed to partly describe its contour along apair of first reference lines extending in parallel; and an insulatinglayer overlaid on the surface of the insulating thin film, saidinsulating layer defining an aperture designed to cross theelectrically-conductive film piece along a second reference lineperpendicular to the first reference lines. In addition, a clearance isestablished for the insertion of the pin in the through bore in thedirection of the second reference line.

When the first flexible printed circuit board is fixed on a headactuator, the first flexible printed circuit is superposed on thesurface of the head actuator. The through bore of the first flexibleprinted circuit board receives the insertion of the pin. The contour ofthe electrically-conductive film piece within the aperture is thendetected with an image recognition apparatus. A shift is thus measuredalong the second reference line in the first flexible printed circuitboard. The amount of shift is measured based on a predeterminedreference position. The first flexible printed circuit board ispositioned on the head actuator based on the amount of shift measured.The positioning of the first flexible printed circuit board can berealized with a high accuracy. Since the predetermined clearance isestablished for the pin within the through bore in the direction of thesecond reference line, the first flexible printed circuit board can bedisplaced on the head actuator for establishment of a higher accuracy.

A specific flexible printed circuit board may be provided to realize theaforementioned recording disk drive. The flexible printed circuit boardcomprises: an insulating thin film; an electrically-conductive filmlocated on the surface of the insulating thin film and designed topartly describe its contour along a pair of first reference linesextending in parallel; an insulating layer overlaid on the surface ofthe insulating thin film, said insulating layer defining an aperturedesigned to cross the electrically-conductive film piece along a secondreference line perpendicular to the first reference lines; and anelongated opening formed at least through the insulating thin film, saidelongated opening extending along the second reference line.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become apparent from the following description of thepreferred embodiments in conjunction with the accompanying drawings,wherein:

FIG. 1 is a plan view schematically illustrating the structure of a harddisk drive (HDD) as an example of a recording disk drive according to anembodiment of the present invention;

FIG. 2 is an enlarged partial perspective view of a first flexibleprinted circuit board along with a fixing member and a clip;

FIG. 3 is an enlarged vertical sectional view illustrating the innerstructure of the first flexible printed circuit and an elastic sheet;

FIG. 4 is an enlarged vertical sectional view of the fixing member andthe first flexible printed circuit board, taken along the line 4-4 inFIG. 1;.

FIG. 5 is an enlarged partial plan view schematically illustrating apart of the first flexible printed circuit board along with a secondflexible printed circuit board;

FIG. 6 is a partial sectional view taken along the line 6-6 in FIG. 5;

FIG. 7 is an enlarged partial plan view, corresponding to FIG. 5,schematically illustrating a part of the first flexible printed circuitboard without the second flexible printed circuit board;

FIG. 8 is an enlarged plan view of apertures in the first flexibleprinted circuit board;

FIG. 9 is an enlarged plan view schematically illustrating alignment ofthe first flexible printed circuit board on a head actuator; and

FIG. 10 is an enlarged plan view schematically illustrating alignment ofthe first flexible printed circuit board on the head actuator accordingto a modified example of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 schematically illustrates the inner structure of a hard diskdrive (HDD) 11 as an example of a recording disk drive or storage deviceaccording to an embodiment of the present invention. The HDD 11 includesa box-shaped main enclosure 12 defining an inner space. At least onemagnetic recording disk 13 is mounted on the driving shaft of a spindlemotor 14 within the main enclosure 12. The spindle motor 14 is allowedto drive the magnetic recording disk 13 for rotation at a higherrevolution speed such as 10,000 rpm, 15,000 rpm, or the like, forexample. A cover, not shown, is coupled to the main enclosure 12 so asto define the closed inner space between the main enclosure 12 and thecover itself.

A head actuator 15 is also accommodated in the inner space of the mainenclosure 12. The head actuator 15 comprises an actuator block 16. Theactuator block 16 is coupled to a vertical support shaft 17 for relativerotation. The rotation of the actuator block 16 allows the head actuator15 to change its attitude relative to the magnetic recording disk 13.Rigid actuator arms 18 are defined in the actuator block 16 so as toextend in the horizontal direction from the vertical support shaft 17.The actuator arms 18 are related to the front and back surfaces of themagnetic recording disk 13. The actuator block 16 maybe made ofaluminum. Molding process maybe employed to form the actuator block 16.

Head suspensions 19 are fixed to the corresponding tip ends of theactuator arms 18. The individual head suspension 19 extends forward fromthe tip end of the actuator arm 18. A flying head slider 21 is supportedon the front end of the head suspension 19. The flying head sliders 21are in this manner connected to the actuator block 16. The flying headsliders 21 are opposed to the surfaces of the magnetic recording disk13. As conventionally known, in the case where two or more magneticrecording disks 13 are incorporated within the inner space of the mainenclosure 12, a pair of the actuator arm 18 as well as a pair of thehead suspension 19 is disposed between the adjacent magnetic recordingdisks 13.

An electromagnetic transducer, not shown, is mounted on the flying headslider 21. The electromagnetic transducer may include a read element anda write element. The read element may include a giant magneto resistive(GMR) element or a tunnel-junction magneto resistive (TMR) elementdesigned to discriminate magnetic bit data on the magnetic recordingdisk 13 by utilizing variation in the electric resistance of a spinvalve film or a tunnel-junction film, for example. The write element mayinclude a thin film magnetic head designed to write magnetic bit datainto the magnetic recording disk 13 by utilizing a magnetic fieldinduced at a thin film coil pattern.

The head suspension 19 serves to urge the flying head slider 21 towardthe surface of the magnetic recording disk 13. When the magneticrecording disk 13 rotates, the flying head slider 21 is allowed toreceive airflow generated along the rotating magnetic recording disk 13.The airflow serves to generate a positive pressure or lift on the flyinghead slider 21. The flying head slider 21 is thus allowed to keep flyingabove the surface of the magnetic recording disk 13 during the rotationof the magnetic recording disk 13 at a higher stability established bythe balance between the urging force of the head suspension 19 and thelift.

A power source such as a voice coil motor (VCM) 22 is connected to theactuator block 17. The power source 22 is designed to drive the actuatorblock 17 for rotation around the support shaft 16. The rotation of theactuator block 17 induces the swinging movement of the actuator arms 18and the head suspensions 19. When the actuator arm 18 is driven to swingabout the support shaft 16 during the flight of the flying head slider21, the flying head slider 21 is allowed to cross the recording tracksdefined on the magnetic recording disk 13 in the radial direction of themagnetic recording disk 13. This radial movement serves to position theflying head slider 21 right above a target recording track on themagnetic recording disk 13.

A flexible printed circuit board unit 23 is superposed on the actuatorblock 16. The flexible printed circuit board unit 23 comprises a firstflexible printed circuit board 24. One end of the first flexible printedcircuit board 24 is attached to a side surface of the actuator block 16.The first flexible printed circuit board 24 bends and extends toward afixing member 25 spaced from the head actuator 15 by a predetermineddistance. The other end of the first flexible printed circuit board 24is superposed on the surface of the fixing member 25. A clip 26 isemployed to hold the other end of the first flexible printed circuitboard 24 on the fixing member 25. The fixing member 25 is a componentseparate from the main enclosure 12.

A head IC (integrated circuit) or preamplifier IC 27 is mounted on thesurface of the first flexible printed circuit board 24. The preamplifierIC 27 is designed to supply the read element with a sensing current whenthe magnetic bit data is to be read. The preamplifier IC 27 is alsodesigned to supply the write element with a writing current when themagnetic bit data is to be written. A small-sized circuit board 28 islocated within the inner space of the main enclosure 12. The circuitboard 28 is designed to supply the preamplifier IC 27 on the flexibleprinted circuit board unit 23 with a sensing and a writing current. Aprinted circuit board, not shown, may be coupled to the back of thebottom plate of the main enclosure 12. The printed circuit board mayalso be designed to supply the preamplifier IC 27 on the flexibleprinted circuit board unit 23 with a sensing and a writing current.

Second flexible printed circuit boards 29 are utilized for supplying thesensing and writing currents. The individual second flexible printedcircuit board 29 is designed to extend from the head suspension 19 tothe actuator block 16. The front end of the second flexible printedcircuit board 29 is superposed on the surface of the head suspension 19.Wiring patterns on the second flexible printed circuit board 29 areconnected to the flying head slider 21. The rear end of the secondflexible printed circuit board 29 is receive don the first flexibleprinted circuit board 24 on the actuator block 16. The wiring patternson the second flexible printed circuit board 29 are connected to wiringpatterns on the first flexible printed circuit board 24. The flying headslider 21 is in this manner electrically connected to the flexibleprinted circuit board unit 23. The second flexible printed circuit board29 is located for the individual actuator arms 18.

As shown in FIG. 2, the flexible printed circuit board unit 23 comprisesan elastic sheet 31. The elastic sheet 31 is overlaid on the surface ofthe first flexible printed circuit board 24. An adhesive layer may beformed on the back surface of the elastic sheet 31. The elastic sheet 31is located at least between the first flexible printed circuit board 24and the clip 26. The clip 26 thus clips all of the fixing member 25, thefirst flexible printed circuit board 24 and the elastic sheet 31superposed one another. The elastic sheet 31 serves to prevent the clip26 from contacting the first flexible printed circuit board 24.

As shown in FIG. 3, the first flexible printed circuit board 24comprises an insulating thin film 32, an electrically-conductive layer33 overlaid on the upper surface of the insulating thin film 32 and aninsulating layer 34 superposed on the upper surface of theelectrically-conductive layer 33. The electrically-conductive layer 33forms wiring patterns extending on the first flexible printed circuitboard 24. The electrically-conductive layer 33 may be made of anelectrically-conductive material such as Cu, for example. The insulatingthin film 32 and the insulating layer 34 may be made of a resin materialsuch as polyimide resin, for example. An adhesive layer, not shown, maybe interposed between the insulating thin film 32 and theelectrically-conductive layer 33 and between the electrically-conductivelayer 33 and the insulating layer 34.

The elastic sheet 31 comprises a viscoelastic layer 35 overlaid on thesurface of the first flexible printed circuit board 24 and a protectinglayer 36 overlaid on the surface of the viscoelastic layer 35. Theviscoelastic layer 35 may be made of a VEM (viscoelastic material), forexample. The protecting layer 36 may be made of a resin material such aspolyimide resin, for example. The protecting layer 36 serves to preventthe viscoelastic layer 35 from deforming. The viscoelastic layer 35 andthe protecting layer 36 may respectively have the thickness ofapproximately 25 μm. As described above, an adhesive layer, not shown,may be formed between the viscoelastic layer 35 and the first flexibleprinted circuit board 24.

As shown in FIG. 4, the clip 26 includes first and second contactingportions 26 a, 26 b extending in parallel. A connecting portion 26cconnects one end of the first contacting portion 26 a with one end ofthe second contacting portion 26 b. The first contacting portion 26 a isdesigned to contact the surface of the elastic sheet 31 on the surfaceof the fixing member 25. The second contacting portion 26 b is designedto contact the back surface of the fixing member 25. The clip 26 has anelasticity to get the first and the second contacting portions 26 a, 26b closer to each other. The clip 26 may be made of a metal material suchas a stainless steel, for example.

The other ends or free ends of the first and second contacting portions26 a, 26 b are designed to gradually bend outward from each other. Thisallows the clip 26 to be smoothly mounted on the fixing member 25without scratching the first flexible printed circuit board 24 and/orthe elastic sheet 31. A bent portion 26 d is also established in thesecond contacting portion 26 b. The second contacting portion 26 b getscloser to the first contacting portion 26 a at the bent portion 26 d.The bent portion 26 d is located adjacent the other or free end of thesecond contacting portion 26 b. It should be noted that a clip of anytype or shape may be employed in place of the aforementioned one.

A groove 37 is formed on the back surface of the fixing member 25. Thegroove 37 extends in a direction perpendicular to the top edge of thefixing member 25. This groove 37 is allowed to guide movement of thebent portion 26 d of the second contacting portion 26 b. A deeperdepression 37 a is formed at the lower end of the groove 37. The deeperdepression 37 a is designed to receive the bent portion 26 d of the clip26. The deeper depression 37 a serves to prevent the clip 26 fromslipping off the fixing member 25.

As shown in FIG. 5, the first flexible printed circuit board 24 is fixedto the side surface of the actuator block 16 with screws 38, forexample. Throughbores or elongated openings 39 are defined in the firstflexible printed circuit board 24. The elongated openings 39 aredesigned to penetrate through at least the insulating thin film 32.Here, two of the elongated opening 39 may be defined in the firstflexible printed circuit board 24, for example. The individual elongatedopening 39 is allowed to receive a pin 41 protruding from the sidesurface of the actuator block 16. Solder materials 42 serve to establishconnection between the pins 41 and the electrically-conductive layer 33of the first flexible printed circuit board 24.

The second flexible printed circuit board 29 is superposed on thesurface of the first flexible printed circuit board 24. As shown in FIG.6, electrically-conductive film pieces 43 are located on the surface ofthe insulating thin film 32. The electrically-conductive film pieces 43are electrically connected to the aforementioned electrically-conductivelayer 33. Apertures 44 are defined in the insulating layer 34 superposedon the surface of the insulating thin film 32. The individual aperture44 is allowed to partly expose the electrically-conductive film piece43. On the other hand, electrically-conductive pads 45 are located onthe second flexible printed circuit board 29. Solder materials 46connects the electrically-conductive film pieces 43 to the correspondingelectrically-conductive pads 45, for example.

As is apparent from FIG. 7, rows of the electrically-conductive filmpieces 43 are arranged in the vertical direction on the first flexibleprinted circuit board 24. Each row includes four electrically-conductivefilm pieces 43 arranged in the horizontal direction. A contour 48 of theelectrically-conductive film piece 43 is allowed to get exposed in theindividual aperture 44 along a pair of first reference line 47 extendingin parallel with each other in the horizontal direction.

The elongated openings 39 are designed to extend along a secondreference line 49 perpendicular to the first reference lines 47. Apredetermined clearance is established for the pin 41 within theelongated opening 39 in the direction of the second reference line 49.This clearance is set larger than a space generally generated due to atolerance. On the other hand, a clearance is eliminated for the pin 41to the uttermost within the elongated opening 39 in the direction of thefirst reference lines 47. The tolerance is reduced to the uttermost inthe direction of the first reference lines 47. The contours 48 of theelectrically-conductive film pieces 43 and the aperture 44 can in thismanner be positioned relative to the elongated opening 39 with arelatively high accuracy.

Through holes 51 are defined in the first flexible printed circuit board24. The through holes 51 are designed to receive insertion of theaforementioned screw 38. A predetermined clearance is established forthe screw 38 within the through hole 51. The clearance is set largerthan at least that of the elongated opening 39.

As is apparent from FIG. 8, the aperture 44 is designed to cross theelectrically-conductive film piece 43 along the second reference line49. The insulating layer 34 is accordingly allowed to cover the oppositeends of the electrically-conductive film pieces 43 in the direction ofthe first reference lines 47. The insulating layer 34 thus partly coversover the contour 48 of the individual electrically-conductive film piece43, so that the electrically-conductive film piece 43 is reliablyprevented from peeling off the insulating thin film 32. Since theadhesive layers are utilized to layer the insulating thin film 32, theelectrically-conductive film pieces 43 and the insulating layer 34, anadhesive 52 leaks inside the apertures 44. The exposed contour 48 maysufficiently be separated from the adhesive 52.

When the flying head slider 21 is positioned, the actuator block 16intermittently repeats rotation around the vertical support shaft 17during the rotation of the magnetic recording disk 13 in theaforementioned HDD 11. The inertial force based on the rotation causesthe first flexible printed circuit board 24 to vibrate when the actuatorblock 16 has stopped rotating. The viscoelastic layer 35 of the elasticsheet 31 serves to absorb this residual vibration. In addition, theprotecting layer 36 serves to improve the performance of theviscoelastic layer 35. The flying head slider 21 is reliably preventedfrom receiving transmission of vibration. The reading and writingoperation of magnetic bit data can be carried out on the magneticrecording disk 13 at a higher accuracy.

Moreover, the elastic sheet 31 serves to prevent the first flexibleprinted circuit board 24 from contacting the clip 26. The protectinglayer 36 serves to protect the first flexible printed circuit board 24.Protection of the insulating layer 34 from damages in this manner servesto avoid exposure of the electrically-conductive layer 33 in the firstflexible printed circuit board 24. The electrically-conductive layer 33can reliably be prevented from short and disconnection. In addition,employment of the clip 26 serves to realize an easier attachment of thefirst flexible printed circuit board 24 to the fixing member 25.Attachment process can be realized in more effective manner. Adouble-sided adhesive tape is interposed between the first flexibleprinted circuit board 24 and the fixing member 25 in a conventional HDD.When the double-sided adhesive tape is to be applied, protection sheetsmust be peeled off from the both sides of the double-sided adhesivetape. This is inefficient.

When the HDD 11 is to be assembled, the flexible printed circuit boardunit 23 is previously prepared. The elastic sheet 31 has been adhered onthe surface of the first flexible printed circuit board 24 in theflexible printed circuit board unit 23. The fixing member 25 ispreviously held on the first flexible printed circuit board 24 with theclip 26. The clip 26 clips the first flexible printed circuit board 24,the elastic sheet 31 and the fixing member 25. The preamplifier IC 27has been mounted on the surface of the first flexible printed circuitboard 24. The flexible printed circuit board unit 23 is fixed to theactuator block 16.

After the flexible printed circuit board unit 23 has been fixed on theactuator block 16, the head suspensions 19 are fixed to the actuatorarms 18. The flying head slider 21 and the second flexible printedcircuit board 29 are previously attached to the individual headsuspension 19. The electrically-conductive pads 43 on the secondflexible printed circuit board 29 are opposed to theelectrically-conductive film pieces 43 on the first flexible printedcircuit board 24. The solder materials 46 are interposed between theelectrically-conductive pads 45 and the electrically-conductive filmpieces 43, respectively. The solder materials 46 are then subjected toheat treatment. The solder materials 46 fuse. When the solder materials46 solidify, electrical connections are established between theelectrically-conductive pads 45 and the electrically-conductive filmpieces 43. The second flexible printed circuit board 29 is thus coupledto the first flexible printed circuit board 24 or flexible printedcircuit board unit 23. The head actuator 15 and the flexible printedcircuit board unit 23 are thereafter incorporated in the main enclosure12 of the HDD 11.

When the flexible printed circuit board unit 23 is fixed on the actuatorblock 16, the first flexible printed circuit board 24 is superposed onthe surface of the actuator block 16 as shown in FIG. 9, for example.The elongated openings 39 of the first flexible printed circuit board 24receive the insertion of the pins 41. Since the clearance is eliminatedto the uttermost in the direction of the first reference lines 47 in theelongated openings 39, the first flexible printed circuit board 24 isaccurately positioned in the horizontal direction.

The contour 48 of the electrically-conductive film piece 43 is detectedwithin the aperture 44 with an image recognition apparatus. A specificnumber of electrically-conductive film pieces 43 may be selected forsuch a detection, for example. A shift is measured in the verticaldirection in the first flexible printed circuit board 24. The amount ofshift is measured based on a predetermined reference position. The firstflexible printed circuit board 24 is positioned on the actuator block 16based on the amount of shift measured. The positioning of the firstflexible printed circuit board 24 can be realized with a high accuracy.In other words, since the predetermined clearance is defined for thepins 41 within the elongated openings 39 in the vertical direction, thefirst flexible printed circuit board 24 can be displaced on the actuatorblock 16 for establishment of a higher accuracy.

After the first flexible printed circuit board 24 has been positioned,the screws 38 are inserted into screw holes 53 defined in the actuatorblock 16. The first flexible printed circuit board 24 or flexibleprinted circuit board unit 23 is thus fixed on the actuator block 16.The pins 41 are thereafter coupled to the electrically-conductive layer33 in the first flexible printed circuit board 24 with the soldermaterials 42 in the elongated openings 39.

Generally, the image recognition apparatus detects the contour 48 of theelectrically-conductive film piece 43 based on detection of a reflectionfrom the electrically-conductive film piece 43 or a reflection from thesolder material attached on the electrically-conductive film piece 43.The adhesive 52 hinders generation of the reflection. As describedabove, when the adhesive 52 leaks inside the apertures 44 over theelectrically-conductive film pieces 43, the image recognition apparatuscannot correctly recognize the electrically-conductive film pieces 43.The image recognition apparatus is unable to recognize the contour 48 ofthe electrically-conductive film piece 43 at a correct position.

As shown in FIG. 10, for example, apertures 54 may also be defined inthe insulating layer 34 in addition to the aforementioned apertures 44.The apertures 54 may be utilized to expose the contours 48 of theelectrically-conductive film pieces 43 along the second reference lines49 on the first flexible printed circuit board 24. The apertures 54 aredesigned to cross the electrically-conductive film pieces 43 in thedirection of the first reference lines 47. The insulating layer 34 isthus allowed to cover over the opposite ends of theelectrically-conductive film pieces 43 in the direction of the secondreference line 49. The insulating layer 34 in this manner partly coversover the contours 48 of the electrically-conductive film pieces 43. Inthis case, a clearance may be established for the pins 41 withinthroughbores 55 which receive the insertion of the pins 41. Theclearance is defined in the directions of the first and second referencelines 47, 49. Like reference numerals are attached to components orstructures equivalent to those of the aforementioned first embodiment.

When the flexible printed circuit board unit 23 is fixed on the actuatorblock 16, the first flexible printed circuit board 24 is superposed onthe surface of the actuator block 16. The image recognition apparatus isthen utilized to detect the contours 48 of the electrically-conductivefilm pieces 43 within the apertures 44, 54. Here, two pairs of theelectrically-conductive film pieces 43 within the apertures 44, 54 maybe selected for such a detection, for example.

A shift is measured in the vertical direction in the first flexibleprinted circuit board 24 for the electrically-conductive film pieces 43within the apertures 44. The amount of shift is measured based on apredetermined reference position. At the same time, a shift is measuredin the horizontal direction in the first flexible printed circuit board24 for the electrically-conductive film pieces 43 within the apertures54. The first flexible printed circuit board 24 is positioned on theactuator block 16 based on the amounts of shift measured. Thepositioning of the first flexible printed circuit board 24 can berealized with a high accuracy. Since the predetermined clearance isdefined for the pins 41 within the through bores 55 in the directions ofthe first and second reference lines 47, 49, the first flexible printedcircuit board 24 can be displaced on the actuator block 16 forestablishment of a higher accuracy.

1. (canceled)
 2. (canceled)
 3. A flexible printed circuit board comprising: an insulating thin film; an electrically-conductive film piece located on a surface of the insulating thin film; an insulating layer overlaid on the surface of the insulating thin film and designed to partly cover over a contour of the electrically-conductive film piece; an aperture formed in the insulating layer so as to expose the contour of the electrically- conductive film piece along a first reference line on the surface of the insulating thin film; and an elongated opening formed at least through the insulating thin film, said elongated opening extending along a second reference line perpendicular to the first reference line.
 4. (canceled)
 5. A flexible printed circuit board comprising: an insulating thin film; an electrically-conductive film piece located on a surface of the thin film and designed to partly describe a contour of the electrically-conductive film piece along a pair of first reference lines extending in parallel; an insulating layer overlaid on the surface of the thin film, said insulating layer defining an aperture designed to cross the electrically-conductive film piece along a second reference line perpendicular to the first reference lines; and an elongated opening formed at least through the thin film, said elongated opening extending along the second reference line.
 6. (canceled) 